I need to calculate the binding energies for the various electrons in a few different molecules (to determine an appropriate wavelength to selectively ionize them). Are there any software packages to ...

For some reason I can't find anything stating it either way explicitly. What I'm talking about is this. Is this difference referring to potential energies or just energies in general? I assume it's ...

I've come across this picture of two linked molecules. The intramolecular distances look similar to the intermolecular distances and it seems like that will be the case however you draw it because of ...

In chemistry it is common sense that we have O$^{2-}$. But from a physical point of view, does O$^{2-}$ really exist as a negative ion? I mean, as an isolated ion.
It is not apparent that a neutral ...

Could someone explain to me how one finds the valence bond wavefunction of an atom?
Take nitrogen for example, I know both nitrogen molecules have a valence-electron configuration of 2s22p1x2p1y2p1z ...

I am thinking of using Hartree-Fock approximation to calculate the ground state energy of helium. The ground state wave function must have a symmetric orbital wave function. But in HF we need a Slater ...

I'm currently writing my dissertation on the application of SCF semi-empirical methods to large systems, in particular proteins, and I'm stuck with a problem: I don't understand why, given the fact ...

Within an atomic orbital, electrons must obviously have relative differences between points in space due to potential gradient. But there is kinetic energy as well. If we choose a particular point as ...

I've just been wondering about how atoms and molecules can be quantum mechanically thought about, and I have a question.
It is often said that intermolecular bonding is purely "electrostatic". I hope ...

Can anyone explain why at a conical intersection the wavefunction changes sign? My understanding is that it is a test to see if the crossing IS indeed a conical intersection or just a coincidence of ...

How can we define spin as the spin of an electron around it's own axis if an electron is described by a probability cloud of finding an electron in a point in space? How does that probability cloud ...

I am currently working my way through John S. Townsend book "A Fundamental Approach to Modern Physics" (ISBN: 978-1-891389-62-7). Exercise 3.12 (p.111) is about the 1D infinite square well. The box ...

What is the rigorous definition of the Aufbau principle and the mathematical model used for its description?
From Wikipedia, we have that the principle postulates a hypothetical process in which an ...

Lets say we have a device that generates plasma fields; if this device creates plasma by heating a gas, where do the electrons that escaped the "orbits" of the atom go?
Would the electron physically ...

I am wondering to what extent the flammability can be predicted from the statistical properties of an ensemble. Given the partition function of an ensemble, can we in principle predict this property? ...

Consider 2-electron integrals over real basis functions of the form
$$
(μν|λσ)=∫dr⃗_1dr⃗_2ϕ_μ(r⃗_1)ϕ_ν(r⃗_1)r^{−1}_{12}ϕ_λ(r⃗_2)ϕ_σ(r⃗_2)
$$
I am told that for a basis set of size $K=100$, there are ...

When a system has a dopant, how much does the Fermi level shift?
For example, say a finite concentration of substitutional dopants replace some bulk atoms, and each has one extra electron. Ignore any ...

What is the quantum mechanical explanation of the octet rule? In other words, what makes the octet rule be true from a quantum mechanical view? How we explain what makes some atoms don't follow the ...

Very basic question.... I know that GAMESS can be used to compute localized molecular orbitals, using for example Boys equation; how does one use the program to get the resulting coefficients used to ...

In many-body solid-state physics, the Coulomb interaction term in the Hamiltonian usually implies the momentum conservation law in indicies:
$$H_c=\frac{1}{2} \sum_{\mathbf{k},\mathbf{k}',\mathbf{q} ...